Research On Energy-efficiency Of Wireless Cellular Network Based On Relay Cooperation

With the rapid development of modern mobile communication technology, people hope to have the capacity to communicate freely without the limit of person, time and place. The appearance of wireless cellular network based on relay cooperation can solve numerous problems that exist in traditional wireless cellular network such as the coverage and capacity issues. So relay cooperation technology would become an especially promising program which can satisfy the needs of high-speed access, large capacity and good quality of services in the future. On the other hand, the energy consumption of communication industry is growing with the improving of communication needs. Nowadays, the issue of green environment protection and energy saving has become the major concerns in the world. Therefore, it is imperative to reduce the energy consumption and improve the energy efficiency of wireless cellular network while meet the demands of communication.In this thesis, we introduce the problem of radio resources tension and high network energy consumption that the existing wireless cellular network face, then expound the necessity of introducing relay collaboration technology, and on the basis of previous studies, summarize the energy efficiency metrics, the characteristics, classification and application of relay cooperative communication systems and the relay collaboration technology. Then we propose two cooperative transmission schemes with high energy efficiency, respectively are energy efficient cooperative transmission scheme based on video service and energy efficient collaboration transmission scheme based on decode transmission. Under the conditions which meet the needs of data and video services of a large number of smart phone users now, according to the large differences exist in the business characteristics and needs between traditional voice services and video services, the former scheme apply a relay cooperative transmission technology to establish the system model and data transmit model, then give the analytical expressions of video transfer process. In the same time, aim to the independence between the immediate request and past state of users, we combine the dynamic programming algorithm and Markov decision processe to solve the the relevant question of user request process. Simulation results show that when there are a large number of hot videos in the network, the proposed cooperative transmission scheme can effectively improve network efficiency. In the latter scheme, we take a full consideration to the link interference factors, outage probability and SINR requirement, analyze the link performance of direct transmission and cooperative transmission. Then we give the analytical expression of power control algorithm based on the half-duplex decode relay cooperative transmission mode. In the end, through the addressing of the non-convex optimization problem, we can get the optimal solution. Simulation results show that the proposed cooperation mode can effectively increase the energy efficiency of the system compared with traditional cellular network transport mechanism and ordinary two-hop relay cellular communication system transmission mechanism.